Introduction: Degenerative spondylolisthesis(DS) results from loss of integrity of discoligamentous structures and facet joints. A number of studies examined increased facet fluid on T2-weighted MRI and spondylolisthesis concluding that there is a correlation between increased facet fluid and instability at the corresponding level. This has been invoked as a prognostic factor supporting surgical treatment. We review the SPORT database, a randomized trial of surgical versus non-surgical treatment for DS focusing on the correlation of facet fluid with radiographic instability and outcome.
Methods: Retrospective analysis of the SPORT database. Individuals with DS at L3-L4 or L4-L5, neurogenic claudication or radiculopathy, and associated neurologic deficit were eligible. Patients were randomized to non-operative or surgical management. The pre-operative MRI was independently reviewed by two blinded neuroradiologists, grading the presence of facet fluid on a scale with proven interreliability from 0(no fluid) to 3(large). Instability was assessed using flexion-extension x-rays defined as >10 degrees of angulation or 4mm of translation. Blinded outcome assessments included SF-36 bodily pain, SF-36 physical function, Oswestry disability index, and back pain bothersome index. Student’s t-test was applied for analysis of significance with alpha of 0.05.
Results: 128 patients met inclusion criteria. 125 patients had any fluid at the spondylitic level but was moderate to large in 71. Comparing patients without facet joint fluid or small effusions to those with moderate to large effusions, there was no significant difference in instability on flexion-extension x-rays (2v8;p=0.2). There was no difference in outcome measures following surgery: SF-36 BP (33.5v35.5;p=0.57), SF-36 PF (37.5v35.8;p=0.57), ODI (42.5v40;p=0.44), back pain bothersome index (4.5v4.1;p=0.24)
Conclusions: Using SPORT data, we found no correlation between increased facet fluid and instability, or between increased fluid and surgical outcome. This suggests that increased facet fluid is not of prognostic importance to surgical treatment of DS.
Patient Care: Addresses the potential use of a radiographic finding as a prognostic factor in surgical outcomes
Learning Objectives: By the conclusion of this session, participants should be able to discuss 1. the appearance of facet joint fluid on MRI; 2. the correlation between increased facet fluid and instability; 3. the correlation between increased facet fluid and surgical outcomes for DS; 4. the SPORT trial for DS